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ELEMENTS OP MATERIA MED1CA.

M. Collard de Martigny (quoted by Dr. Christison) experienced weight in thehead, obscurity of sight, pain in the temples, ringing in the ears, giddiness, andan undefinable feeling of terror. Tuken into the stomach, dissolved in water, orin the form of effervescing draughts, it allays thirst, and diminishes preterna-tural heat, thus acting like the other dilute acids. If it be evolved in the sto-mach, it distends this viscus, excites eructations, and checks both nausea andvomiting. It appears to promote the secretions of the alimentary tube, to assistthe digestive process, to allay irritation, and to act as a refreshing and exhilaratingsubstanee. It is said to be diuretic and diaphoretic. Wöhler and Stehbergerexpressly State, that the use of carbonic acid did not increase the quantity of thissubstanee in the urine. (Duncan, Supplement to the Edinb. Disp. p. 223.)When drunk too quickly, and in large quantity, water impregnated with this gashas beeil known to excite giddiness and intoxication; (Fodere, Med. Legate.) andit is probable that Champagne is indebted to this substanee for part of its intoxi-cating powers. Applied to ulcers and suppurating surfaces, carbonic acid gasacta as a stimulant, improves the quality of the discharge in ill-conditioned andindolent ulcers, retards the putrefaction of the secreted matters, diminishes theunpleasant odour of foul and gangrenous sores, and promotes the Separation ofthe dead and mortified parts.

Uses. «.. When inhaled. —In some diseases of the lungs, particularly phthisis,it has been proposed to mix carbonic acid gas with the atmospheric air breathedby the patient, with the view of lessening the stimulant influence of the oxygen,to diminish the quantity and improve the quality of the matter expectorated, andat the same time to relieve the hectic Symptoms. But the practice is dangerous.Part of the benefit said to have been derived by consumptive patients froni a resi-dence in cow-houses, has been ascribed to the inhalatibn of carbonic acid gas(see p. 54.)

ß. Taken into the stomach, carbonic acid is a most valuable remedy for check-ing vomiting, and diminishing irritable conditions of this viscus. The best modeof exhibiting it is, 1 believe, in the form of an effervescing draught, composed ofeitric acid and bicarbonate of potash. In fever, it is an excellent refrigerant;especially serviceable in those cases which are aecompanied with gastric irrita-tion. In that form of lithiasis attended with a white or phosphatic deposite inthe urine, carbonic acid water may be taken with advantage; but in this case thecommon effervescing draught (made of a vegetable acid and a carbonated alkali)must not bc substituted for it, on aecount of the alkaline propeTty communicatedby the latter to the urine. From its antiseptic qualities, carbonic acid has beenadministered internally, in those diseases which are supposed to be connectedwith a putrescent tendency, as typhoid fevers, &c. (See Dobson's MedicalCommentary on Fixed Air, 2nd ed. Lond. 1785.)

y. Clysters of carbonic acid gas have been employed in certain affections ofthe rectum and colon,—for example, ulceration of the rectum, especially whenof the kind commonly denominated cancerous. Mr. Parkin 1 has recommendedthem in dysentery. The gas may be introduced into the rectum from a bladder,or Solutions of tartaric acid and bicarbonate of soda may be injeeted in the usualway.

}. A siream of carbonic acid gas has been applied to the Uterus with greatbenefit, in a painful condition of this viscus, as I have already mentioned (see p.161.)

£. Applied to the skin, care being taken that the gas be not inhaled, it is em-ployed either in its gaseous form, or dissolved in water. It is, of course, adaptedto those cases where it is desirable to excite the vascular System, especially ofthe skin, and to cause Perspiration; while, on the other band, it is objectionable

1 On the Ejjicaey of Carbonic Jicid Gas in the Diseases of Tropical Cümates; with Directiovs for the Treat-ment of Jicute and Chronic Sktgea of Dysentery. Reviewed in the London Medical Gazette, vol. xviii. p. 777.]83t>.